This invention relates to apparatus for cleaning floors, carpets and the like and is more particularly concerned with a dual purpose apparatus suitable for both dry suction cleaning ("vacuum" cleaning) and for wet process cleaning operations involving the application and removal of a liquid. Such apparatus is sometimes known as a "three-in-one" appliance since, in addition to performing normal dry vacuuming operations and wet cleaning operations, it can also be used simply for drying floors or picking up spillages.
Many designs have been proposed for such dual purpose appliances, but the concept of interchangeability between wet and dry modes of operation has successfully been applied only in the context of vacuum cleaners of the so-called "canister" type in which a cleaning implement to which suction is applied is connected to a source of suction within a body of the appliance by means of a flexible hose. In general, the body of appliances of the canister type can be made relatively large and, indeed, heavy because, whilst it is mobile (on castors or the like) it is not required to be moved constantly back and forth by the user.
However, an alternative form of vacuum cleaner which is in common use is the so-called "upright" type in which a main cleaning implement is carried by a body of the appliance together with a source of suction so that the appliance as a whole is normally required to be moved back and forth by the user. Thus, different constraints on size and weight apply in the case of vacuum cleaners of the upright type, and for this reason it has not previously been possible to provide a commercially successful cleaner of the upright type which is capable of operating in both wet and dry modes.
In our British Patent specifications 1601456 and 2038168 there are disclosed two vacuum cleaners of the canister type in which a reservoir assembly for a cleaning liquid and a filter assembly for the separation of dry dust are interchangeably assembled between a source of suction and a collection container which is thereby adapted for either wet or dry operation. Thus the main body of the appliance in either mode of operation comprises three sections which are releasably clipped together, the central section comprising either of the two interchangeable sections. Such an arrangement is generally satisfactory for vacuum cleaners of the canister type because they stand stably on the floor and the user can use two hands to manipulate the various components as necessary without undue difficulty.
Whilst, theoretically, such a three-section construction could be adopted for a vacuum cleaner of the upright type, in practice this has a number of disadvantages to the user in particular.
Even where the upright cleaner is of the kind which includes a base member, in which the main cleaning implement and motor/impeller unit are located, with a swivellably connected handle portion carrying the collection container, so that the appliance as a whole can stand stably on the floor with the handle assembly in an upright position, the appliance is generally less stable than a cleaner of the canister type, partly because of its greater height and partly because of the swivellable connection between the handle assembly and the base member, so that manipulation of interchangeable sections to convert from wet to dry mode may be difficult. The difficulties would be even greater with a vacuum cleaner of the so-called "stick" type in which the cleaning implement is not incorporated in a base member whereby the appliance as a whole can stand in a stable manner on the floor.
Our International Patent specifications WO94/17722 and WO94/17723 disclose an appliance of the stick type in which the collection container is removably housed within a recess formed in a body of the appliance, but without any provision for conversion between wet and dry modes of operation, the collection container being removably coupled at its upper end to an air/liquid separator disposed non-removably within the body of the appliance.